That issue is:
If we create a high-pixel-count image with microshift technique and a lower-pixel-count sensor, and wish to attain resolution commensurate with the potential of the pixel count, can we do that with a lower-performance lens than if we had created the high-pixel-count image in the regular way with a sensor having the pixel count we want for the image?
Doug
True Doug… that's exactly what the "real" question is! However, we have to also take into account other factors than sensor pixel count, like sensor size, lens uniformity across its image circle, image area to lens mount distance and all other factors… The truth is, that as with with all sensor sizes, (Aps-c, FF etc) with MF sensors, the more the pixel count increases, the result on resolution increase is less visible… (i.e. a P45+ (39mp) is no where near than presenting almost double the resolution than a P25+) while if MS (4x) is used, the difference appears to be huge although there is no increase at all of pixel count… For example, a Hasselblad H3D-39ms used in 4xMS, not only appears to have much more resolving power than if shot at single shot, but also easily outperforms a Hassy H4D-60… Now, if one compares an 80mp back, with a 22mp of the past, with the best possible lens used on both used at its best aperture (say Leaf 12 vs Leaf 22 with the new 120micro at f11 fitted on a Mamyia or P1 6x4.5 camera) there is a clearly visible resolution difference, but on an 111x148cm print, you may say that what you see is maybe 35% of more resolution than the 350% difference that the pixel count suggests.
Now, 16xMS was only available until a couple of years ago on 22mp backs, all the higher resolution ones where only able to do 4x MS… this was because the piezoelectric crystal that was used to do the sensor movements, wasn't mechanically (it was and probably still is technologically restricted) able to accurately control movements of less than 4.5μM… However, if you do the above test (i.e. print 111x148cm) to compare 22mp 4xMS vs. 88mp 16xMS using the same sensor and you use
an absolutely superb tripod like my 40 years old FATIF (I was given that masterpiece from a very old now retired photographer) you won't believe your eyes when comparing the two prints… There is clearly four times the resolution present! OTOH, if you use my Manfroto 058 and re-perform the same test, the difference drops to something like 50-80% depending on the shutter speed used!
Which leads us to the following results:
1. Even the best of lenses don't "like" small pixels…
2. MS is far superior (in resolving power only - if the rest of qualities (colour, DR etc) come into account it is simply incomparable) to same resolution single shot and visibly better at even more than double the pixel count.
3. MS is greatly dependant of other variants (movement accuracy, constant lighting, vibration etc), it is not a situation where it either fails or its done right, one may think that it was done well (because he got no "error" or "movement detection" sensed on the software) but still he may be under the wrong impression!
4. 16x is of four times the resolution than 4xMS, but it is far more sensitive to the MS variants (obviously because the magnitude of sensor movement is so small thus much more vulnerable).
I hope I've helped your thoughts... One more thing, ...before I got the Fatif tripod (a couple of years ago) I
thought I was doing 16x correctly, in fact I thought that I was mastering it …it was only after I got the Fatif that I realised why so many people think of MS as a PIN to do… If its done correctly it's exactly as easy as doing a long exposure… Pay some more attention to that saying of mine which I will repeat…
I have 100% success doing 16x with Fuji GX680… most will tell you that even 4x is impossible with the Fuji!